Cyclic Peptide Keap1-Nrf2 Protein-Protein Interaction Inhibitors: Design, Synthesis, and In Vivo Treatment of Acute Lung Injury.

Directly blocking the Keap1-Nrf2 pathway is a promising strategy for the mitigation of acute lung injury (ALI). Peptide Keap1-Nrf2 inhibitors have been reported to have a high Keap1 binding affinity. However, these inhibitors showed weak activity in cells and/or animals. In this study, we designed a series of linear peptides from an Nrf2-based 9-mer Ac-LDEETGEFL-NH2. To improve the cellular activity, we further designed cyclic peptides based on the crystal complex of Keap1 with a linear peptide. Among them, cyclic 9-mer ZC9 targeting Keap1 showed a better affinity (KD2 = 51 nM). Specifically, it exhibited an acceptable water solubility (>38 mg/mL), better cell permeability, cell activity, and metabolic stability (serum t1/2 > 24 h). In the in vitro LPS-induced oxidative damages and ALI model, ZC9 showed significant dose-response reversal activity without apparent toxicity. In conclusion, our results suggested ZC9 as a lead cyclic peptide targeting the Keap1-Nrf2 pathway for ALI clinical treatment.

Cyclic peptide conjugated photosensitizer for targeted phototheranostics of gram-negative bacterial infection.

Antimicrobial photodynamic therapy (PDT) is a promising alternative to antibiotics for eradicating pathogenic bacterial infections. It holds advantage of not inducing antimicrobial resistance but is limited for the treatment of gram-negative bacterial infection due to the lack of photosensitizer (PS) capable of targeted permeating the outer membrane (OM) of gram-negative bacteria. To facilitate the targeted permeability of PS, cyclic polymyxin b nonapeptide that can specifically bind to the lipopolysaccharide on OM, is conjugated to an FDA approved PS chlorin e6 via variable linkers. Based on structure to activity study, C6pCe6 with aminohexanoic linker and P2pCe6 with amino-3, 6-dioxaoctanoic linker are identified to preferentially image gram-negative bacteria. These two conjugates also exhibit improved aqueous dispersity and enhanced ROS generation, consequently enabled their selective bactericidal activities against gram-negative bacteria upon 660 nm light irradiation. The effective photobactericidal ability of P2pCe6 is further validated on P. aeruginosa infected G. mellonella. Moreover, it is demonstrated to effectively treat the P. aeruginosa infection and accelerate the healing process at the wound site of mouse. Owing to the light irradiation triggered targeted imaging and enhanced bactericidal capacities, P2pCe6 hold great potential to serve as a potent PS for mediating the phototheranostics of gram-negative bacterial infection.

Long-acting somatostatin analogs and well differentiated neuroendocrine tumors: a 20-year-old story.

PURPOSE: The specific indications of somatostatin analogs (SSAs) in patients with neuroendocrine tumor (NET) emerged over the time. The objective of this review is to summarize and discuss the most relevant data concerning long-acting SSAs in NET. METHODS: A narrative review was performed including publications focusing on therapy with the long-acting octreotide, lanreotide, and pasireotide in patients with NET. RESULTS: Long-acting SSAs confirm to be a manageable and widely used tool in patients with NET. Both long-acting octreotide and lanreotide are safe as the short-acting formulations, while patient compliance and adherence is further improved. Together with some randomized phase-3 trials, many retrospective and prospective studies have been performed in the last 20 years revealing a variable but substantial impact on progression free survival, not only in gastroenteropancreatic but also in lung and unknown primary NETs. The most frequent tumor response to SSAs is stable disease, but an objective response can be observed, more frequently by using high-dose schedules and in MEN1-related pancreatic NETs. Low tumor burden, low tumor grade (G1 and low G2), good performance status and use as first-line therapy are the main predictive factors to SSAs in NET patients. Pasireotide has been evaluated in few studies. This compound remains a promising SSA and would deserve to be further evaluated as a potential additional indication in NET therapy. CONCLUSIONS: Long-acting SSAs are an effective and safe initial therapy of patients with well differentiated NET, allowing tumor growth as well as symptoms control for long-time in selected patients.

Unlocking novel therapies: cyclic peptide design for amyloidogenic targets through synergies of experiments, simulations, and machine learning.

Existing therapies for neurodegenerative diseases like Parkinson's and Alzheimer's address only their symptoms and do not prevent disease onset. Common therapeutic agents, such as small molecules and antibodies struggle with insufficient selectivity, stability and bioavailability, leading to poor performance in clinical trials. Peptide-based therapeutics are emerging as promising candidates, with successful applications for cardiovascular diseases and cancers due to their high bioavailability, good efficacy and specificity. In particular, cyclic peptides have a long in vivo stability, while maintaining a robust antibody-like binding affinity. However, the de novo design of cyclic peptides is challenging due to the lack of long-lived druggable pockets of the target polypeptide, absence of exhaustive conformational distributions of the target and/or the binder, unknown binding site, methodological limitations, associated constraints (failed trials, time, money) and the vast combinatorial sequence space. Hence, efficient alignment and cooperation between disciplines, and synergies between experiments and simulations complemented by popular techniques like machine-learning can significantly speed up the therapeutic cyclic-peptide development for neurodegenerative diseases. We review the latest advancements in cyclic peptide design against amyloidogenic targets from a computational perspective in light of recent advancements and potential of machine learning to optimize the design process. We discuss the difficulties encountered when designing novel peptide-based inhibitors and we propose new strategies incorporating experiments, simulations and machine learning to design cyclic peptides to inhibit the toxic propagation of amyloidogenic polypeptides. Importantly, these strategies extend beyond the mere design of cyclic peptides and serve as template for the de novo generation of (bio)materials with programmable properties.

An Overview on Antimalarial Peptides: Natural Sources, Synthetic Methodology and Biological Properties.

Peptide compounds play a significant role in medicinal chemistry as they can inhibit the activity of species that cause malaria. This literature review summarizes the isolation of antimalarial peptides, the synthesis method with the detailed structure and sequences of each peptide, and discusses the biological activity of the isolated and synthesized compounds. The synthetic routes and reactions for cyclic and linear antimalarial peptides are systematically highlighted in this review including preparing building blocks, protection and deprotection, coupling and cyclization reactions until the target compound is obtained. Based on the literature data and the results, this review's aim is to provide information to discover and synthesize more antimalarial peptide for future research.

Therapeutic Potential of Marine-Derived Cyclic Peptides as Antiparasitic Agents.

Parasitic diseases still compromise human health. Some of the currently available therapeutic drugs have limitations considering their adverse effects, questionable efficacy, and long treatment, which have encouraged drug resistance. There is an urgent need to find new, safe, effective, and affordable antiparasitic drugs. Marine-derived cyclic peptides have been increasingly screened as candidates for developing new drugs. Therefore, in this review, a systematic analysis of the scientific literature was performed and 25 marine-derived cyclic peptides with antiparasitic activity (1-25) were found. Antimalarial activity is the most reported (51%), followed by antileishmanial (27%) and antitrypanosomal (20%) activities. Some compounds showed promising antiparasitic activity at the nM scale, being active against various parasites. The mechanisms of action and targets for some of the compounds have been investigated, revealing different strategies against parasites.

Covalent Peptide LSD1 Inhibitor Specifically Recognizes Cys360 in the Enzyme-Active Region.

Lysine-specific demethylase 1 (LSD1) is a promising therapeutic target, especially in cancer treatment. Despite several LSD1 inhibitors being discovered for the cofactor pocket, none are FDA-approved. We aimed to develop stabilized peptides for irreversible LSD1 binding, focusing on unique cysteine residue Cys360 in LSD1 and SNAIL1. We created LSD1 C360-targeting peptides, like cyclic peptide S9-CMC1, using our Cysteine-Methionine cyclization strategy. S9-CMC1 effectively inhibited LSD1 at the protein level, as confirmed by MS analysis showing covalent bonding to Cys360. In cells, S9-CMC1 inhibited LSD1 activity, increasing H3K4me1 and H3K4me2 levels, leading to G1 cell cycle arrest and apoptosis and inhibiting cell proliferation. Remarkably, S9-CMC1 showed therapeutic potential in A549 xenograft animal models, regulating LSD1 activity and significantly inhibiting tumor growth with minimal organ damage. These findings suggest LSD1 C360 as a promising site for covalent LSD1 inhibitors' development.

OPERA: perception of information in patients with gastroenteropancreatic neuroendocrine tumors on lanreotide autogel.

IMPORTANCE: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can affect patient health-related quality of life (HRQoL). Appropriate information may improve their adherence to treatment and quality of life. OBJECTIVE: To evaluate the change in patient's perceptions of the level of information at lanreotide (LAN) treatment initiation for GEP-NETs vs after 6 months. DESIGN: OPERA (NCT03562091) was a prospective, longitudinal, noninterventional study. SETTING: Thirty-one centers in France specialized in the management of patients with NETs. INTERVENTION: Planned clinical visits at enrollment and end-of-study visits at month 6, with completion of the European Organisation for Research and Treatment of Cancer 25-item Quality of Life Questionnaire-Information Module (QLQ-INFO25) and 30-item Quality of Life Questionnaire-Core. MAIN OUTCOME: Absolute change in the patient's perception of the information between baseline and month 6, using the relevant domains of the QLQ-INFO25. Endpoints measured at baseline and month 6 for at least 1 of the 3 targeted QLQ-INFO25 dimensions of the primary endpoint. RESULTS: Ninety-three of the 115 patients enrolled completed ≥1 primary endpoint information dimension. Mean (SD) scores for the primary endpoint information dimensions were high at baseline (disease, 63.41 [20.71]; treatment, 58.85 [19.00]; supportive care, 26.53 [24.69]; maximum 100). There were no significant changes between baseline (98.34% CI) and 6 months (disease, -2.84 [-8.69, 3.01; P = .24]; treatment, -4.37 [-11.26, 2.52; P = .13]; supportive care, 0.46 [-6.78, 7.70; P = .88]), and in HRQoL between baseline and 6 months. CONCLUSIONS AND RELEVANCE: The lack of change in patient's perceptions of the disease, treatment, and supportive care information provided over the first 6 months of LAN treatment may suggest that physicians provided adequate information at the treatment initiation.

Cyclic helix B peptide alleviates proinflammatory cell death and improves functional recovery after traumatic spinal cord injury.

BACKGROUND: Necroptosis and pyroptosis, two types of proinflammatory programmed cell death, were recently found to play important roles in spinal cord injury (SCI). Moreover, cyclic helix B peptide (CHBP) was designed to maintain erythropoietin (EPO) activity and protect tissue against the adverse effects of EPO. However, the protective mechanism of CHBP following SCI is still unknown. This research explored the necroptosis- and pyroptosis-related mechanism underlying the neuroprotective effect of CHBP after SCI. METHODS: Gene Expression Omnibus (GEO) datasets and RNA sequencing were used to identify the molecular mechanisms of CHBP for SCI. A mouse model of contusion SCI was constructed, and HE staining, Nissl staining, Masson staining, footprint analysis and the Basso Mouse Scale (BMS) were applied for histological and behavioural analyses. qPCR, Western blot analysis, immunoprecipitation and immunofluorescence were utilized to analyse the levels of necroptosis, pyroptosis, autophagy and molecules associated with the AMPK signalling pathway. RESULTS: The results revealed that CHBP significantly improved functional restoration, elevated autophagy, suppressed pyroptosis, and mitigated necroptosis after SCI. 3-Methyladenine (3-MA), an autophagy inhibitor, attenuated these beneficial effects of CHBP. Furthermore, CHBP-triggered elevation of autophagy was mediated by the dephosphorylation and nuclear translocation of TFEB, and this effect was due to stimulation of the AMPK-FOXO3a-SPK2-CARM1 and AMPK-mTOR signalling pathways. CONCLUSION: CHBP acts as a powerful regulator of autophagy that improves functional recovery by alleviating proinflammatory cell death after SCI and thus might be a prospective therapeutic agent for clinical application.

Discovery and Design of Novel Cyclic Peptides as Specific Inhibitors Targeting CCN2 and Disrupting CCN2/EGFR Interaction for Kidney Fibrosis Treatment.

Kidney fibrosis is a serious consequence of chronic kidney disease (CKD), and currently, there is no effective pharmacological treatment available. Cellular communication network-2 (CCN2/CTGF) is an extracellular matrix (ECM) protein that regulates the fibrotic process by activating the epidermal growth factor receptor (EGFR) signaling pathway. We herein present the discovery and structure-activity relationship study of novel peptides targeting CCN2 to develop potent and stable specific inhibitors of the CCN2/EGFR interaction. Remarkably, the 7-mer cyclic peptide OK2 exhibited potent activities to inhibit CCN2/EGFR-induced STAT3 phosphorylation and cellular ECM protein synthesis. Subsequent in vivo studies demonstrated that OK2 significantly alleviated renal fibrosis in a unilateral ureteral obstruction (UUO) mouse model. Moreover, this study first revealed that the peptide candidate could efficiently block CCN2/EGFR interaction through binding to the CT domain of CCN2, providing a new alternative strategy for peptide-based targeting of CCN2 and modulating CCN2/EGFR-mediated biological functions in kidney fibrosis.

Antimicrobial Peptides and Small Molecules Targeting the Cell Membrane of Staphylococcus aureus.

Clinical management of Staphylococcus aureus infections presents a challenge due to the high incidence, considerable virulence, and emergence of drug resistance mechanisms. The treatment of drug-resistant strains, such as methicillin-resistant S. aureus (MRSA), is further complicated by the development of tolerance and persistence to antimicrobial agents in clinical use. To address these challenges, membrane disruptors, that are not generally considered during drug discovery for agents against S. aureus, should be explored. The cell membrane protects S. aureus from external stresses and antimicrobial agents, but membrane-targeting antimicrobial agents are probably less likely to promote bacterial resistance. Nontypical linear cationic antimicrobial peptides (AMPs), highly modified AMPs such as daptomycin (lipopeptide), bacitracin (cyclic peptide), and gramicidin S (cyclic peptide), are currently in clinical use. Recent studies have demonstrated that AMPs and small molecules can penetrate the cell membrane of S. aureus, inhibit phospholipid biosynthesis, or block the passage of solutes between the periplasm and the exterior of the cell. In addition to their primary mechanism of action (MOA) that targets the bacterial membrane, AMPs and small molecules may also impact bacteria through secondary mechanisms such as targeting the biofilm, and downregulating virulence genes of S. aureus. In this review, we discuss the current state of research into cell membrane-targeting AMPs and small molecules and their potential mechanisms of action against drug-resistant physiological forms of S. aureus, including persister cells and biofilms.

Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists.

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

Design and Discovery of Novel Cyclic Peptides as EDPs-EBP Interaction Inhibitors for the Treatment of Liver Fibrosis.

Liver fibrosis is the undesirable result of excessive deposition of the extracellular matrix (ECM), and elastin is known as one of the key ECM components. Under specific pathological conditions, elastin undergoes degradation to produce elastin-derived peptides (EDPs), which bind to elastin-binding protein (EBP) to activate corresponding signal pathways, thus accelerating fibrosis progression. Herein, we describe the discovery of novel cyclic peptides that function as potent and stable inhibitors to interfere with the peptide-protein interaction between EDPs and EBP. Remarkably, CXJ-2 exhibited potent activities to inhibit the PI3K/ERK pathway and decrease hepatic stellate cell proliferation and migration. The subsequent in vivo study demonstrated that CXJ-2 possessed potent antifibrotic efficacy in ameliorating CCl4-induced liver fibrosis. This work provides a successful pharmacological strategy for the development of novel inhibitors of EDPs-EBP interaction, which sheds new light on how cyclic peptides disrupt peptide-protein interaction and may also provide new structure-oriented therapeutic candidates in liver fibrosis.

Pharmacokinetics of Novel Oral Cyclic Peptide.

Protein and peptide drugs have been considered to be valuable for treating disease for many years, capturing more and more of the attention of researchers. Previously, we found a short peptide from the porcine intestine named COX52-69, which could simultaneously lower blood glucose and insulin response after intraperitoneal injection. And thus, it showed a potential to counter type II diabetes without leading to insulin resistance, mainly caused by high insulin levels in the blood. However, this molecule is not stable in the digestive system and cannot be used via oral administration. Here we employed the circularization technique to modify the peptide and tested its pharmacokinetics.

Cyclopeptide-based Anti-liver Cancer Agents: A Mini-review.

Chemotherapy is one of the most important treatment modalities for liver cancer, especially for those who are judged as being unsuitable for surgical resection, local ablative therapy, or transarterial chemoembolization. However, the efficacy of chemotherapy is still unsatisfactory due to the long duration, side effects and the tendency to develop drug resistance. The development of novel anti-liver cancer drugs remains imperative. Cyclopeptides have been recognized as new chemical modalities in drug design due to their unique constrained structures, extensive biological activities, higher metabolic stability, cell permeability and bioavailability than linear peptides. A lot of cyclic peptides have been found with potential anti-proliferative activity against malignant cells, and many of them showed excellent anti-liver cancer activity. In this review, we will discuss in detail the structures and the anti-liver cancer activity of small and medium-sized cyclopeptides, aiming to offer some elicitation to chemotherapeutic drug design based on cyclopeptides.

Rheumatoid arthritis study of the Egyptian College of Rheumatology (ECR): nationwide presentation and worldwide stance.

To depict the spectrum of rheumatoid arthritis (RA) in Egypt in relation to other universal studies to provide broad-based characteristics to this particular population. This work included 10,364 adult RA patients from 26 specialized Egyptian rheumatology centers representing 22 major cities all over the country. The demographic and clinical features as well as therapeutic data were assessed. The mean age of the patients was 44.8 ± 11.7 years, disease duration 6.4 ± 6 years, and age at onset 38.4 ± 11.6 years; 209 (2%) were juvenile-onset. They were 8750 females and 1614 males (F:M 5.4:1). 8% were diabetic and 11.5% hypertensive. Their disease activity score (DAS28) was 4.4 ± 1.4 and health assessment questionnaire (HAQ) 0.95 ± 0.64. The rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) were positive in 73.7% and 66.7% respectively. Methotrexate was the most used treatment (78%) followed by hydroxychloroquine (73.7%) and steroids (71.3%). Biologic therapy was received by 11.6% with a significantly higher frequency by males vs females (15.7% vs 10.9%, p = 0.001). The least age at onset, F:M, RF and anti-CCP positivity were present in Upper Egypt (p < 0.0001), while the highest DAS28 was reported in Canal cities and Sinai (p < 0.0001). The HAQ was significantly increased in Upper Egypt with the least disability in Canal cities and Sinai (p = 0.001). Biologic therapy intake was higher in Lower Egypt followed by the Capital (p < 0.0001). The spectrum of RA phenotype in Egypt is variable across the country with an increasing shift in the F:M ratio. The age at onset was lower than in other countries.

Rheumatoid meningitis without a history of rheumatoid arthritis: a case report and literature review.

Rheumatoid meningitis (RM) is a rare extra-articular manifestation of rheumatoid arthritis, usually with non-specific symptoms. In most cases, head magnetic resonance imaging (MRI) shows lamellar enhancements in leptomeninges and pachymeninges, but definitive diagnosis relies on meningeal biopsies. Here, we reported a 43-year-old RM patient without a previous history of rheumatoid arthritis. He came to seek medical assistance because of fever and headache. The head MRI showed bilateral enhancements in leptomeninges and pachymeninges, and blood tests showed that serum IgM rheumatoid factor (RF) (1010.0 IU/ml) and anti-cyclic citrullinated peptide (CCP) antibody (654.24 RU/ml) became positive with a further increase with the progression of the disease. After treatment with steroids, clinical symptoms were relieved. We also reviewed previous history, symptoms, and serum, cerebrospinal fluid and imaging findings in 15 RM cases without a history of rheumatoid arthritis published since 2010. Consistent with previous reported cases, the current case suggests importance of meningeal biopsies and increases in serum RF and anti-CCP antibody in diagnosis of RM. In addition, previous joint symptoms and chronic headaches, and leptomeningeal and pachymeningeal lesions on head MRI are also of great significance for the diagnosis.

Prescription patterns of somatostatin analogs in patients with acromegaly and neuroendocrine tumors.

PURPOSE: Acromegaly and neuroendocrine tumors are rare diseases that, under certain conditions, can be treated with somatostatin analogs. The aim was to determine the prescription patterns of somatostatin analogs in a group of patients with acromegaly and neuroendocrine tumors affiliated with the Colombian Health System. METHODS: A retrospective study. A cohort of patients from a drug dispensing database that collected all prescriptions of long-acting somatostatin analogs (octreotide, lanreotide, pasireotide). Sociodemographic variables, clinical variables (diagnosis and comorbidities) and pharmacological therapy variables (dose, changes, persistence of use, comedications) were considered. RESULTS: A total of 213 patients were identified, including 139 (65.3%) with acromegaly and 74 (34.7%) with neuroendocrine tumors. There was a predominance of women (58.7%) and a mean age of 59.7 ± 14.5 years. The most commonly used medications were lanreotide autogel (n = 107; 50.2%), octreotide LAR (n = 102; 47.9%) and pasireotide LAR (n = 4; 1.9%). During follow-up, 11.3% of patients experienced modifications of therapy, with a mean duration from the beginning of treatment to the change in medication of 25 ± 15.9 months. A total of 48.9% of the patients with acromegaly and 87.1% of individuals with neuroendocrine tumors received maximum approved doses of the drug. CONCLUSION: Patients with acromegaly and neuroendocrine tumors in Colombia are mainly women and are most frequently treated with lanreotide autogel for acromegaly and with octreotide LAR for neuroendocrine tumors. In addition, a high proportion are managed with maximum doses of long-acting somatostatin analogs.

A systematic literature review to evaluate extended dosing intervals in the pharmacological management of acromegaly.

PURPOSE: This systematic literature review investigated whether extended dosing intervals (EDIs) of pharmacological acromegaly treatments reduce patient burden and costs compared with standard dosing, while maintaining effectiveness. METHODS: MEDLINE/Embase/the Cochrane Library (2001-June 2021) and key congresses (2018-2021) were searched and identified systematic literature review bibliographies reviewed. Included publications reported on efficacy/effectiveness, safety and tolerability, health-related quality of life (HRQoL), and patient-reported and economic outcomes in longitudinal/cross-sectional studies in adults with acromegaly. Interventions included EDIs of pegvisomant, cabergoline, and somatostatin receptor ligands (SRLs): lanreotide autogel/depot (LAN), octreotide long-acting release (OCT), pasireotide long-acting release (PAS), and oral octreotide; no comparator was required. RESULTS: In total, 35 publications reported on 27 studies: 3 pegvisomant monotherapy, 11 pegvisomant combination therapy with SRLs, 9 LAN, and 4 OCT; no studies reported on cabergoline, PAS, or oral octreotide at EDIs. Maintenance of normal insulin-like growth factor I (IGF-I) was observed in ≥ 70% of patients with LAN (1 study), OCT (1 study), and pegvisomant monotherapy (1 study). Achievement of normal IGF-I was observed in ≥ 70% of patients with LAN (3 studies) and pegvisomant in combination with SRLs (4 studies). Safety profiles were similar across EDI and standard regimens. Patients preferred and were satisfied with EDIs. HRQoL was maintained and cost savings were provided with EDIs versus standard regimens. CONCLUSIONS: Clinical efficacy/effectiveness, safety, and HRQoL outcomes in adults with acromegaly were similar and costs lower with EDIs versus standard regimens. Physicians may consider acromegaly treatment at EDIs, especially for patients with good disease control.

Development of a cyclic-inverso AHSG/Fetuin A-based peptide for inhibition of calcification in osteoarthritis.

OBJECTIVE: Ectopic calcification is an important contributor to chronic diseases, such as osteoarthritis. Currently, no effective therapies exist to counteract calcification. We developed peptides derived from the calcium binding domain of human Alpha-2-HS-Glycoprotein (AHSG/Fetuin A) to counteract calcification. METHODS: A library of seven 30 amino acid (AA) long peptides, spanning the 118 AA Cystatin 1 domain of AHSG, were synthesized and evaluated in an in vitro calcium phosphate precipitation assay. The best performing peptide was modified (cyclic, retro-inverso and combinations thereof) and evaluated in cellular calcification models and the rat Medial Collateral Ligament Transection + Medial Meniscal Tear (MCLT + MMT) osteoarthritis model. RESULTS: A cyclic peptide spanning AA 1-30 of mature AHSG showed clear inhibition of calcium phosphate precipitation in the nM-pM range that far exceeded the biological activity of the linear peptide variant or bovine Fetuin. Biochemical and electron microscopy analyses of calcium phosphate particles revealed a similar, but distinct, mode of action in comparison with bFetuin. A cyclic-inverso variant of the AHSG 1-30 peptide inhibited calcification of human articular chondrocytes, vascular smooth muscle cells and during osteogenic differentiation of bone marrow derived stromal cells. Lastly, we evaluated the effect of intra-articular injection of the cyclic-inverso AHSG 1-30 peptide in a rat osteoarthritis model. A significant improvement was found in histopathological osteoarthritis score and animal mobility. Serum levels of IFNγ were found to be lower in AHSG 1-30 peptide treated animals. CONCLUSIONS: The cyclic-inverso AHSG 1-30 peptide directly inhibits the calcification process and holds the potential for future application in osteoarthritis.